My ramblings about all things technical

PowerEdge 6950 shows 112GB of RAM even though 128GB is installed

For the past few days we’ve had the above problem where we upgraded one of our PowerEdge 6950 server to 128Gb of RAM but once we booted it it only showed 112GB of RAM. My colleague James Voll and I tested to try work out which RAM bank may have been causing the issue and found one where if we removed the two RAM sticks it still only showed 112GB so we contacted Dell and got an engineer out who replaced the motherboard for us but still after the replacement it wasn’t showing the full amount. in actual fact due to the motherboard coming with the basic BIOS update it only showed 12GB!! So we updated the BIOS to the latest revision and it was still showing 112GB. I logged into the BIOS and went to the memory settings for the server and noticed “Server Memory Test” was enabled so decided to disable it and reboot the server to see if possibly it would change something and remarkably it seems it did as now the server showed 128GB of RAM and booted twenty times faster through the post screen. I’m not if it’s a bug or because the 6950’s don’t normally have that amount of RAM in them but disabling the Server Memory Test feature seems to have given back our missing 16GB of RAM

Hope this saves someone the time and effort it took for us to work it out